Figure on getting to your resort around 7 with DME. Normally would say just explore your resort(if you haven't stayed before), and since you are at Pop, you can walk over the bridge to check out AoA , which is very well themed, especially Cars section IMHO, if you haven't seen it . Their food court is also better if you were grabbing QS.
However, since you are on PST and will likely not go to bed early, you could make a late dinner ADR, like 8 on to give you time to travel there after check-in, and probably more your usual dinner time anyway! (You can also Uber if time is tighter rather than waiting for bus) You could eat somewhere either TS or QS on the monorail route to get in the mood seeing MK and the castle, and possibly catching sights of fireworks afterwards. Could also eat at Boardwalk area and catch some entertainment there or see part of Illuminations from International Gateway area. Or since you are close to AK, so could head there and hop bus to eat at AKL, and check out animals on the Savannah and the resort if you haven't seen it - very impressive! And of course there is always DS to eat and start your souvenir shopping!
Just a note on checked luggage - it is supposed to take 3- 4 hours from when you get to resort to arrive if you let DME pick it up, so if you want to have it before 10-11 pm, you will want to go grab it yourself to bring on the bus(and then don't use yellow tags).